A136010 solved

[franktaw at netscape.net]

See below for the answer.

Franklin T. Adams-Watters

-----Original Message-----
From: Don Reble <djr at nk.ca>

Seqfans, njas, Jordan:

> %I A136010
> %S A136010 
20,9,243,1782,14661,118665,962604,7806213,63306927,513404406
> %N A136010 From an online IQ test (Adaptive IQ ). Solution not known
>            to the submitter.

    a(1)=20, a(2)=9, a(n+2) = 7*a(n+1) + 9*a(n).

    Quick puzzle: What's lim (n->+inf) a(n+1)/a(n) ?
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That would be the larger root of x^2-7x-9, which is (7+sqrt(85))/2, or 
8.1097722286464436550011371408814....